RE: Recording user commands (from RE: Linux-audit Digest, Vol 31, Issue 12)

RE: Recording user commands (from RE: Linux-audit Digest, Vol 31, Issue 12)

[Taylor_Tad]

  
  
  -----Original Message-----
While a little more verbose than one might like, couldn't you audit
exec() system calls?  That would certainly capture all the commands
issued from a shell.  However, you might want to only audit successful
exec()s.  As I recall from auditing *nix systems years ago, shells tend
to just start trying to execute a command name along your path and if it
fails, it tries again with the next path (for example, the command
doesn't exist in /usr/local/bin, let's try /usr/bin and then /usr/sbin,
etc.)  
  This would pick up other exec()s as well, but you should be able to
generate reports to find the ones that were issued by a shell.  Just a
thought.
  --Tad Taylor
  
  Message: 3
  Date: Thu, 26 Apr 2007 11:10:05 -0400
  From: Steve Grubb <sgrubb@redhat.com>
  Subject: Re: Recording user command ?
  To: linux-audit@redhat.com
  Message-ID: <200704261110.05440.sgrubb@redhat.com>
  Content-Type: text/plain;  charset="iso-8859-1"
  
  On Thursday 26 April 2007 10:32, Gavin White wrote:
  > In addition to recording system calls, file activity etc, I would
like
  > to record issued commands, ie. anything typed into a shell by a
user.
  >
  > Is this a reasonable thing to do with auditd? Is it possible?
  
  Well, there are 2 kinds of users, root and everyone else. What
everyone else 
  does cannot be logged by the session they are running in because it
does not 
  have enough privileges to log to the audit system.
  
  For the root user, it has enough privileges to log. We are working on
a 
  solution for this problem. I think most security targets are only
interested 
  in actions performed by the root user since they can affect the
machine in 
  many ways.
  
  So, as it stands today, it can't be done with the audit system. We
hope to 
  have something that starts to address the problem soon.
  
  -Steve
  
  
  
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  End of Linux-audit Digest, Vol 31, Issue 12
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Re: Recording user commands (from RE: Linux-audit Digest, Vol 31, Issue 12)

[Steve Grubb]

On Friday 27 April 2007 16:05, Taylor_Tad@emc.com wrote:
> While a little more verbose than one might like, couldn't you audit
> exec() system calls?

Yes, you could certainly do that. But as you said, it would be more data than 
you would want. If you had a policy of no root logins, you could define a 
rule something like this:

-a always,entry -S execve -F 'auid>=500'

And that should cut it down to the commands run by real users and not daemons.

>However, you might want to only audit successful exec()s.

I don't think execve returns in the normal sense when successful.

-Steve

Re: Recording user commands (from RE: Linux-audit Digest, Vol 31, Issue 12)

[Paul Moore]

On Friday, April 27 2007 4:05:28 pm Taylor_Tad@emc.com wrote:
> While a little more verbose than one might like, couldn't you audit
> exec() system calls?  That would certainly capture all the commands
> issued from a shell.

I believe that would miss all of the shell built-in commands though, wouldn't 
it?  Not sure if we would care, but you can do some interesting things with 
the built-ins ... (although maybe you could capture that through additional 
audit watches/syscalls/etc.)

-- 
paul moore
linux security @ hp

Re: Recording user commands (from RE: Linux-audit Digest, Vol 31, Issue 12)

[Valdis.Kletnieks]

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On Fri, 27 Apr 2007 16:28:17 EDT, Paul Moore said:

> I believe that would miss all of the shell built-in commands though, wouldn't
> it?  Not sure if we would care, but you can do some interesting things with 
> the built-ins ... (although maybe you could capture that through additional 
> audit watches/syscalls/etc.)

# perl -e 'while (<>) {eval $_;}'

Doing proper auditing of what a user is doing is harder than it looks.
Have a nice day. :)

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